Review of RESMD data base in the group of patients with MDS from diagnosis of low risk myelodysplastic syndrome (MDS) and occurrence of anemia that began treatment with erythropoiesis stimulating agent (ESAs) / support transfusional before December 31, 2011. In all cases, data obtained will be prior to the date of the start of the study to ensure its retrospective nature, thus reflecting the routine use of erythropoietic agents in clinical and non-interference in the doctor's clinical practice.